Need shock tuning advice for 1600

Jorge Rodriguez

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for starters I noticed that in the video you don´t have the spare, you should test it with the spare to see how it will handle under racing conditions, plus the added weight might help a little with what seems to be a kicking rear end...
 

ASHCRAFT

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The torsions are Kartek 23mm. I will only run a spare on none lap races such San felipe, Baja 500, or the 1000. I dont like having the extra weight if it isnt necessary. Since I plan on running lap races such as Barstow, lucerne, and Plaster city to start with I would like to have the car dialed without a spare. Then add a turn or two into the preload to compensate for the extra weight of a tire. But if it takes a spare to keep down that is what I will do.
 

David_Girdner

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It does seem to be rebounding too fast and kicking. We're running the same shocks (single seat 1600 with 23mm bars) and sent them back after the first race to be revalved because we had to close off both rebound tubes to get it to where we were happy with it. Another thing to try is to open the "long" compression tube to soften up the initial part of the travel.
 

Mark Newhan

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It does not appear in the video that you are using much of the wheel travel. The "kick" looks like it is most likely a "stacking up" problem, not a rebound issue.

How are the bypass tubes laid out (compression), and how are they adjusted?
 

FlyHiFlyLo

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ASHCRAFT said:
Alright boys. Went to plaster city yesterday for the first test run on my 1600. I need some advice on tuning the rear shocks before I head back out. The rear shocks are 3.0 4 tube King bypass. Thanks for the help. http://media.putfile.com/Ashcraft-1600-first-run

Seems to run well. Little extra tweaking should be real fast.
 

ASHCRAFT

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Thank you guys for the input and positive feedback. 1-2/1600 is one of the most competitive classes out there. I cant wait to have this car on the race track. Mark and Cheater you guys are awsome. See you guys at the Tree Bar in sept.
 
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Mark Newhan said:
It does not appear in the video that you are using much of the wheel travel. The "kick" looks like it is most likely a "stacking up" problem, not a rebound issue.

How are the bypass tubes laid out (compression), and how are they adjusted?

Mark is seeing what I see. It would be nice to be able to see the video in super slow motion, it makes it much easier to see the wheel travel. I would agree with Mark's stacking observation. It does not look like you are getting full range of motion. Put some zip ties on the shock shafts to see how much up travel you are getting then open up the long compression bypass tube all the way and see if this yields more up travel. It also looks like there is not enough rebound control within the travel range that you are getting, but also looks like you are not getting full droop out of it so that there is too much rebound at the bottom of the travel - or not enough preload in the bars.

In general, and especially when working on initial setup, I like to make drastic changes to bypass tube settings to see what the effect is. Half a turn or one or two turns is not enough to realize if you are taking it in the right direction. The analogy I like to use is this: If I handed you a 3' piece of tubing and told you to find the middle and balance it on your finger you would have a hard time finding it. But if you stuck out one finger on each hand and rested the tube across them at the ends of the tube then you could easily find the center by moving your fingers together towards the middle of the tube until they touch and that will be the center and it will balance.

Use this same technique to tune you car; start with too much compression (this is where you are at now) then open it up all the way and see if there is now not enough compression and the work towards the middle. I hope this makes sense and helps.
 

cosmo

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David_Girdner said:
It does seem to be rebounding too fast and kicking. We're running the same shocks (single seat 1600 with 23mm bars) and sent them back after the first race to be revalved because we had to close off both rebound tubes to get it to where we were happy with it. Another thing to try is to open the "long" compression tube to soften up the initial part of the travel.


?? Open up the "short' comp. tube to soften the initial part of of the comp. stroke. Ramsey makes a good point. Try a couple of turns on the Long comp. tube. This will control the last third of travel. Once past the bypass tube(long tube), the valving is all that is controlling the shocks action.
 

ASHCRAFT

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Thank you Ramsey for the help. After speaking with you, I will be changing my bass-ackward way of bypass tuning. Your theories and information have been a great help. I will be out testing again on wednesday. I will pass some video your way for sure.
 

Brad Falin

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If it were me and I lived in CA, I would go run the car at primm in NV that to me is the roughest stuff out there, see how it does there, Mark and Ramsey are right on all the travel not being used, what did the mfg say about the shock tuning? Maybe try running the spare in the next test run to see if it helps
 

ASHCRAFT

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Brad Falin said:
If it were me and I lived in CA, I would go run the car at primm in NV that to me is the roughest stuff out there, see how it does there, Mark and Ramsey are right on all the travel not being used, what did the mfg say about the shock tuning? Maybe try running the spare in the next test run to see if it helps
Well I put in two calls on thursday and two calls on friday to King. Emailed my short video to Brett. No reply. But thats alright. Ramsey and Mark answerd all my questions over the phone. Both gave me some great information. As far as a spare goes the 230 lb one around my gut gives some 1600 racers an advatage over me. yeah fat guy in a little car. So I try to run as light as possible. Primm is one of the only lap races you will see me run with a spare. I guarantee a huge improvment the next time out.
 

Brad Falin

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The reason I asked on the support is I had the same results. That is what led me down the path I am on today, great car Make sure you have a good prep, A good prep far outweighs a car that does'nt that does not work correctly for a nice finish:D
 

Tipracer

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Without actually bieng there its real hard to give you some pointers but from what I saw you need to tighten it up, your rebound seems to be OK but I would add compression stiffness, call the guys @ KING and tell them your car is kicking up and trying to swap ends, they will know exactly what you need to try first, good luck!!!:)
 
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